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4000122704-1
18 Fault Finding
Before trying to operate the boiler make sure that :
• All gas supply cocks are open and that the gas supply has
been purged of air.
• The heating system pressure is at least 1 bar.
• There is a permanent mains supply to the boiler.
• The fuse on the PCB is intact.
WARNING. Always isolate the boiler from the electrical supply
before carrying out any electrical replacement work.
Always check for gas soundness after any service work.
Should there be any doubt about the voltage supply to any of
the components, it is possible to carry out a simple electrical
test to ensure all is operational in that area.
To carry out the electrical test, gain access to the main Printed
Circuit Board (PCB), as described previously, and measure
the voltages according to table 2.
TYPE OF FAULT
CHECK
No domestic hot water (F30E Only)
• 230V supply
No central heating
• Is fuse blown
(No flashing warning light on control panel)
• Loose connections on control board (PCB)
• Wrong flue length
• Connections on air pressure switch (electrical or tubes)
disconnected
• Faulty control or interface board (PCB's)
No domestic hot water (F30E Only)
• Water pressure
No central heating
• Shortage of air or gas
(A flashing warning light on control panel)
• Faulty temperature sensor
• Overheating
(F30E Only)
• 230V supply
No central heating, but hot water at taps
• Fuse blown
• Loose connections on control board (PCB).
• Wrong flue length
• Connections on air pressure switch (electrical or tubes)
disconnected
• Faulty control board or interface board (PCB's).
Voltage
Measured value
Measuring point
230 Volt
230V AC
Between terminals H8.1 and H8.2
24 Volt
maximum 33V DC
Between terminals J2.4 and J2.7
minimum 20V DC
15 Volt
15V
±
0.5V
Between terminals J2.4 and J2.2
Display
5V
±
0.5V
Between terminals J2.4 and J4.2
Table 2
IMPORTANT: On completion of the fault finding task which has
required the breaking or remaking of the electrical connections,
the continuity, polarity, short circuit and resistance to earth
checks must be repeated using a suitable multimeter.
